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Dive into the research topics where Keigo Bunsen is active.

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Featured researches published by Keigo Bunsen.


international solid-state circuits conference | 2011

A 60-GHz 16QAM/8PSK/QPSK/BPSK Direct-Conversion Transceiver for IEEE802.15.3c

Kenichi Okada; Ning Li; Kota Matsushita; Keigo Bunsen; Rui Murakami; Ahmed Musa; Takahiro Sato; Hiroki Asada; Naoki Takayama; Shogo Ito; Win Chaivipas; Ryo Minami; Tatsuya Yamaguchi; Yasuaki Takeuchi; Hiroyuki Yamagishi; Makoto Noda; Akira Matsuzawa

This paper presents a 60-GHz direct-conversion transceiver using 60-GHz quadrature oscillators. The transceiver has been fabricated in a standard 65-nm CMOS process. It in cludes a receiver with a 17.3-dB conversion gain and less than 8.0-dB noise figure, a transmitter with a 18.3-dB conversion gain, a 9.5-dBm output 1 dB compression point, a 10.9-dBm saturation output power and 8.8-% power added efficiency. The 60-GHz frequency synthesizer is implemented by a combination of a 20-GHz PLL and a 60-GHz quadrature injection-locked oscillator, which achieves a phase noise of -95 dBc/Hz@l MHz-offset at 60 GHz. The transceiver realizes IEEE802.15.3c full-rate wireless communication for all 16QAM/8PSK/QPSK/BPSK modes, and the communication distances with the full data rate using 2.16-GHz bandwidth, measured with an antenna built in the package, are 2.7-m (BPSK/QPSK) and 0.2-m (8PSK/16QAM). The measured maximum data rates are 8 Gb/s in QPSK mode and 11 Gb/s in 16QAM mode over a 5 cm wireless link within a bit error rate (BER) of <;10-3. The transceiver consumes 186 mW from a 1.2-V supply voltage while transmitting and 106 mW from 1.0-V supply voltage while receiving. Both transmitter and receiver are driven by a 20-GHz PLL, which consumes 66 mW, including output buffer, from a 1.2-V supply voltage.


IEEE Journal of Solid-state Circuits | 2013

Full Four-Channel 6.3-Gb/s 60-GHz CMOS Transceiver With Low-Power Analog and Digital Baseband Circuitry

Kenichi Okada; Keitarou Kondou; Masaya Miyahara; Masashi Shinagawa; Hiroki Asada; Ryo Minami; Tatsuya Yamaguchi; Ahmed Musa; Yuuki Tsukui; Yasuo Asakura; Shinya Tamonoki; Hiroyuki Yamagishi; Yasufumi Hino; Takahiro Sato; Hironori Sakaguchi; Naoki Shimasaki; Toshihiko Ito; Yasuaki Takeuchi; Ning Li; Qinghong Bu; Rui Murakami; Keigo Bunsen; Kota Matsushita; Makoto Noda; Akira Matsuzawa

This paper presents a 60-GHz direct-conversion RF front-end and baseband transceiver including analog and digital circuitry for PHY functions. The 65-nm CMOS front-end consumes 319 and 223 mW in transmitting and receiving mode, respectively. It is capable of more than 7-Gb/s 16QAM wireless communication for every channel of the 60-GHz standards, which can be extended up to 10 Gb/s. The 40-nm CMOS baseband including analog, digital, and I/O consumes 196 and 427 mW for 16QAM in transmitting and receiving modes, respectively. In the analog baseband, a 5-b 2304-MS/s ADC consumes 12 mW, and a 6-b 3456-MS/s DAC consumes 11 mW. In the digital baseband integrating all PHY functions, a (1440, 1344) LDPC decoder consumes 74 mW with the low energy efficiency of 11.8 pJ/b. The entire system including both RF and BB using a 6-dBi antenna built in the organic package can transmit 3.1 Gb/s over 1.8 m in QPSK and 6.3 Gb/s over 0.05 m in 16QAM.


international solid-state circuits conference | 2012

A full 4-channel 6.3Gb/s 60GHz direct-conversion transceiver with low-power analog and digital baseband circuitry

Kenichi Okada; Keitarou Kondou; Masaya Miyahara; Masashi Shinagawa; Hiroki Asada; Ryo Minami; Tatsuya Yamaguchi; Ahmed Musa; Yuuki Tsukui; Yasuo Asakura; Shinya Tamonoki; Hiroyuki Yamagishi; Yasufumi Hino; Takahiro Sato; Hironori Sakaguchi; Naoki Shimasaki; Toshihiko Ito; Yasuaki Takeuchi; Ning Li; Qinghong Bu; Rui Murakami; Keigo Bunsen; Kota Matsushita; Makoto Noda; Akira Matsuzawa

This paper presents a 60 GHz direct-conversion front-end and baseband transceiver, including analog and digital circuitry for the PHY functions. The 65 nm CMOS front-end consumes 319 mW and 223 mW in transmitting and receiving mode, respectively, and is capable of more than 7 Gb/s 16QAM wireless communication for every channel of the 60 GHz standards. The 40 nm CMOS baseband incorporating LDPC consumes 196 mW and 398 mW for 16QAM in transmitting and receiving mode, respectively. The entire system, using a 6dBi antenna built in an organic package, can transmit 3.1Gb/s over 1.8 m in QPSK and 6.3 Gb/s over 0.05 m in 16QAM.


european solid-state circuits conference | 2010

A 24 dB gain 51–68 GHz CMOS low noise amplifier using asymmetric-layout transistors

Ning Li; Keigo Bunsen; Naoki Takayama; Qinghong Bu; Toshihide Suzuki; Masaru Sato; Tatsuya Hirose; Kenichi Okada; Akira Matsuzawa

At mm-wave frequency, the layout of CMOS transistors has a larger effect on the device performance than ever before in low frequency. In this work, the distance between the gate and drain contact (Dgd) has been enlarged to obtain a better maximum available gain (MAG). A 0.6 dB MAG improvement is realized when Dgd changes from 60 nm to 200 nm. By using the asymmetric-layout transistor, a four-stage common-source low noise amplifier is implemented in a 65 nm CMOS process. A measured peak power gain of 24 dB is achieved with a power dissipation of 30 mW from a 1.2-V power supply. An 18 dB variable gain is also realized by adjusting the bias voltage. The measured 3-dB bandwidth is about 17 GHz from 51 GHz to 68 GHz, and noise figure (NF) is from 4.0 dB to 7.6 dB.


asian solid state circuits conference | 2011

A 60GHz 16Gb/s 16QAM low-power direct-conversion transceiver using capacitive cross-coupling neutralization in 65 nm CMOS

Hiroki Asada; Keigo Bunsen; Kota Matsushita; Rui Murakami; Qinghong Bu; Ahmed Musa; Takahiro Sato; Tatsuya Yamaguchi; Ryo Minami; Toshihiko Ito; Kenichi Okada; Akira Matsuzawa

This paper presents a 16QAM direct-conversion transceiver in 65nm CMOS, which is capable of 60-GHz wireless standards. The capacitive cross-coupling neutralization contributes a high common-mode rejection and a high reverse isolation, and a fully-balanced mixer can improve the error vector magnitude due to the reduced local leakage. The maximum data rates with an antenna built in a package are 10Gb/s in QPSK mode and 16Gb/s in 16QAM mode and the transmitter and the receiver consume 181mW and 138 mW, respectively.


asia-pacific microwave conference | 2009

A multi-line de-embedding technique for mm-wave CMOS circuits

Naoki Takayama; Kouta Matsushita; Shogo Ito; Ning Li; Keigo Bunsen; Kenichi Okada; Akira Matsuzawa

This paper proposes a de-embedding method for on-chip S-parameter measurements at mm-wave frequency. The proposed method uses only two transmission lines with different length. In the proposed method, a parasitic-component model extracted from two transmission lines can be used for de-embedding for other-type DUTs like transistor, capacitor, inductor, etc. The experimental results show that the error in characteristic impedance between the different-length transmission lines is less than 1Ω.


asia pacific microwave conference | 2012

A 60GHz power amplifier using high common-mode rejection technique

Ryo Minami; Keigo Bunsen; Kenichi Okada; Akira Matsuzawa

This paper proposes the method of realization of high common-mode rejection ratio(CMRR) at 60 GHz. High CMRR can compensate the differential mismatch. In the proposed method, virtual ground for differential-mode and LC peaking for common-mode are utilized. To confirm the effect of this technique, the 2-stage differential power amplifier is fabricated in a 65nm CMOS process. It achieves a CMRR of 26 dB, a power gain of 12.1 dB, a peak PAE of 11.1%, a Psat of 9.0 dBm, a power consumption of 45.8mW from a 1.0V power supply.


european microwave conference | 2011

A 60GHz CMOS power amplifier using capacitive cross-coupling neutralization with 16 % PAE

Hiroki Asada; Kota Matsushita; Keigo Bunsen; Kenichi Okada; Akira Matsuzawa


asia-pacific microwave conference | 2010

Evaluation of a multi-line de-embedding technique for millimeter-wave CMOS circuit design

Qinghong Bu; Ning Li; Keigo Bunsen; Hiroki Asada; Kota Matsushita; Kenichi Okada; Akira Matsuzawa


IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences | 2012

A 24 dB Gain 51–68 GHz Common Source Low Noise Amplifier Using Asymmetric-Layout Transistors

Ning Li; Keigo Bunsen; Naoki Takayama; Qinghong Bu; Toshihide Suzuki; Masaru Sato; Yoichi Kawano; Tatsuya Hirose; Kenichi Okada; Akira Matsuzawa

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Akira Matsuzawa

Tokyo Institute of Technology

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Kenichi Okada

Tokyo Institute of Technology

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Ning Li

Tokyo Institute of Technology

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Kota Matsushita

Tokyo Institute of Technology

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Hiroki Asada

Tokyo Institute of Technology

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Naoki Takayama

Tokyo Institute of Technology

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Qinghong Bu

Tokyo Institute of Technology

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Ryo Minami

Tokyo Institute of Technology

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Ahmed Musa

Tokyo Institute of Technology

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Rui Murakami

Tokyo Institute of Technology

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